by Oren Dorell, USA TODAY

by Oren Dorell, USA TODAY

A massive Russian aid convoy bringing supplies to residents in a besieged rebel stronghold in eastern Ukraine idled 12 miles from the Ukrainian border Thursday as the Ukrainian national government and Red Cross discussed what to do with it.

"The convoy has arrived. The ICRC (International Committee of the Red Cross) is in contact with the Russian leader of this convoy," ICRC spokesman André Loersch said in the Ukrainian capital, Kiev.

The convoy's 262 trucks parked in a lot in Russia's Rostov region, as another ICRC representative talked to Ukrainian officials about how to inspect the contents and bring the goods into the country.

Russia says the goods include food, generators and medical supplies for civilians in the city of Luhansk. Ukraine's government, which is fighting pro-Russian separatists, threatened to block the convoy if the cargo could not be inspected. The Kiev government, which fears Russia is trying to smuggle arms and other assistance to the rebels, announced it was organizing its own shipment of humanitarian aid.

The United States has warned Russia about the convoy. "Russia has no right to send vehicles or persons or cargo of any kind into Ukraine without the government's explicit permission," U.S. State Department spokeswoman Marie Harf said Thursday.

Leaders in Ukraine and the West have accused Moscow of providing arms and expertise to pro-Russian rebels in east Ukraine, who have been battling government forces since April. Moscow has denied those charges, but the breakdown in communication over humanitarian aid has further stoked fears of Russian intervention.

As negotiations over the convoy continued, separatist leader Valery Bolotov, head of the self-proclaimed Luhansk People's Republic, said Thursday he was resigning from his role because of injuries he received in the fighting, according to Russian state-owned media. Bolotov is the second senior rebel leader to resign in a week. Alexander Borodai, a Moscow political consultant who headed the Donetsk People's Republic, resigned on Aug. 7.

The huge line of white trucks, some flying the red flag of Moscow and accompanied by green military vehicles, traveled down a winding highway through sunflower fields and rolling green hills.

Laurent Corbaz, the ICRC's head of operations for Eastern Europe and Central Asia, arrived Thursday in Kiev for talks with government officials, Loersch said. Corbaz will go to Moscow Saturday to continue talks with Russian officials.

Loersch said the ICRC does not have the manpower to inspect all the vehicles in the convoy. It will not participate in organizing the distribution of goods without the cooperation of both countries, he said.

The ICRC position is that "at some point, Ukrainian authorities should check the contents of the trucks," Loersch said. "Ukraine, like any other state, has a say on what kind of items are crossing its borders."

Andriy Lysenko, a spokesman for Ukraine's National Security and Defense Council, said if the Russians refuse to allow inspection of its cargo, "movement of the convoy will be blocked with all the forces available."

As the standoff continued, the Ukrainian government announced Thursday that it was dispatching its own aid to the region. Ukrainian Infrastructure Minister Maxim Burbak said three convoys totaling 75 trucks are transporting 800 tons of humanitarian aid from Kiev to the cities of Kharkiv and Dnipropetrovsk. Burbak said the aid included grain, sugar and tinned food, and was destined eventually for Luhansk .

Attempts to ease the humanitarian crisis came as Ukrainian forces stepped up efforts to dislodge the rebels from their last strongholds in Donetsk and Luhansk with heavy shelling. In Donetsk, a city of 1 million before the fighting, the city council urged residents to stay off the streets.

The U.N.'s human rights office in Geneva said Wednesday that its "very conservative estimates" show the overall death toll has risen to at least 2,086 people as of Aug. 10, up from 1,129 on July 26. Hundreds of thousands of Ukrainians have been displaced by the fighting, Loersch said.

Also Thursday, Russian President Vladimir Putin said his goal was "to stop bloodshed in Ukraine as soon as possible." He delivered his remarks in the Black Sea resort of Yalta in Crimea, which Russia annexed from Ukraine in March.